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path: root/src/thread/pthread_rwlock_tryrdlock.c
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Diffstat (limited to 'src/thread/pthread_rwlock_tryrdlock.c')
-rw-r--r--src/thread/pthread_rwlock_tryrdlock.c14
1 files changed, 7 insertions, 7 deletions
diff --git a/src/thread/pthread_rwlock_tryrdlock.c b/src/thread/pthread_rwlock_tryrdlock.c
index f860ec71..fa271fcc 100644
--- a/src/thread/pthread_rwlock_tryrdlock.c
+++ b/src/thread/pthread_rwlock_tryrdlock.c
@@ -2,12 +2,12 @@
int pthread_rwlock_tryrdlock(pthread_rwlock_t *rw)
{
- a_inc(&rw->_rw_readers);
- if (rw->_rw_wrlock) {
- a_dec(&rw->_rw_readers);
- if (rw->_rw_waiters && !rw->_rw_readers)
- __wake(&rw->_rw_readers, 1, 0);
- return EBUSY;
- }
+ int val, cnt;
+ do {
+ val = rw->_rw_lock;
+ cnt = val & 0x7fffffff;
+ if (cnt == 0x7fffffff) return EBUSY;
+ if (cnt == 0x7ffffffe) return EAGAIN;
+ } while (a_cas(&rw->_rw_lock, val, val+1) != val);
return 0;
}